The effect of slag variability in the attempted manufacture of AYF (alite-ye'elimite-ferrite) cement clinker at both laboratory and pilot scale

• Published in: Cement (Amsterdam, Netherlands) Vol. 16; p. 100098
• Main Authors: Isteri, Visa, Ohenoja, Katja, Rößler, Christiane, Kletti, Holger, Tanskanen, Pekka, Illikainen, Mirja, Hanein, Theodore, Fabritius, Timo
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.06.2024; Elsevier
• Subjects: Alite; AOD slag; Calcium sulphoaluminate cement; Clinkering; Mineralisation; Scale-up; Waste valorisation; Ye'elimite; A; Clinkering; $; Ye'elimite; F; Alite; M; Scale-up; Cement oxide notation: C; AOD slag; S; T; Waste valorisation; Calcium sulphoaluminate cement; Mineralisation
• ISSN: 2666-5492; 2666-5492
• DOI: 10.1016/j.cement.2024.100098

•Alite-ye'elimite clinker was produced in laboratory and pilot scale.•Fluorine-bearing AOD slag was used for the first time for mineralisation of alite.•In pilot scale in a 7 m kiln, the produced clinker was BYF instead.•Ternesite with fluorine and sodium substitution was found to be a minor phase. The production of AYF (alite-ye'elimite-ferrite) clinker was tested at laboratory and semi-industrial scale using by-products from the metallurgical industry: AOD slag; ladle slag; and fayalitic slag. Alite could be produced with ye'elimite using fluorine originating from AOD (argon oxygen decarburisation) slag as a mineraliser. After a successful laboratory demonstration, the clinker production was scaled to a semi-industrial trial. It was discovered that the reason for the absence of alite formation in a semi-industrial demonstration was that the AOD slag from the specific batch did not perform the designed mineralisation effect for alite formation. This study demonstrates that alite-ye'elimite can be produced at 1260 °C at laboratory scale by using fluorine mineralisation originating from an industrial by-product – in this case, AOD slag. However, the utilisation of by-products for delicate reactions requires detailed determination of the properties of the slag, as the variability from the same source yields different clinker chemistries and mineral phases.